The APS liquid nitrogen distribution system (LNDS) was installed in 2000 to supply APS beamlines with a continuous supply of liquid nitrogen (LN2).
The LNDS allows beamlines to connect directly to a very large, stable supply of LN2, reducing the need for manually filling portable dewars along with the expense and potential for disruption of the supply.
In 2010, the APS experienced a series of LN2 events that resulted in significant disruption to some beamlines. The original 3,000-gallon supply tanks were undersized relative to the demand for LN2, which had grown over the years. This resulted in some of the tanks requiring refill every day, complicated by changing weather conditions, truck mechanical breakdowns, delivery schedule conflicts and even medical emergencies. This became an operational disruption at the APS when LN2 delivery failures required opening of interconnect valves, which swept accumulated water contamination into the system, changing from water to ice along the way, eventually clogging beamline equipment.